As wireless technologies proliferate, mobile wireless devices incorporate systems based on a multiplicity of different wireless standards. Such devices are capable of accessing multiple wireless networks simultaneously, and are referred to herein as “combo” devices.
Wireless networks accessed by a combo device may use overlapping or adjacent portions of the wireless spectrum. For example, BLUETOOTH and IEEE 802.11b/g/n based networks both utilize the 2.4-2.5 GHz band. Access to the networks can be coordinated via time multiplexing or frequency multiplexing to reduce performance degradation caused by collisions/interference that may occur when the networks are simultaneously accessed. Such multiplexing reduces the medium time available to each radio and consequently lowers network performance, as a radio may be blocked from transmitting or receiving packets temporally to avoid collision and/or interference with the colocated radio.
Wireless transceivers are one major source of energy consumption in battery powered mobile/embedded devices. Assigning a low power state (i.e., a sleep state or doze state) to a transceiver is one technique for improving energy efficiency in such a device. While in the sleep state, some or all components of a radio transceiver are turned off or operate in a reduced power state, which greatly reduces energy consumption. A transceiver is unable to access the wireless medium while in the sleep state.